This invention relates to a method and apparatus for the analysis of food material, such as meat products, and more particularly to an improved process for quick and accurate determination of the percentage of fat, moisture, and protein in products such as beef, pork, combinations thereof, and the like. Related methods are disclosed in U.S. Pat. Nos. 3,673,852, 3,890,825, and 3,916,670 to the assignee of this application.
In meat products which are intended for human consumption and which are comminuted during processing, the accurate control of fat and/or moisture content arises. Typical of such meat products are ground beef, pork, veal, lamb, pork sausage and meat products such as bologna, weiners, and liverwurst. The usual procedure is to feed chunk meat into a grinder and then into a mixer to bring about intermixing of the meat product ingredients. It is after the mixing operation that the composition is checked and adjustments made in the fat to lean ratio and/or moisture content. Following this, the meat is then ground a second time or further processed by mixing and blending with seasonings and the like and checked again for compositional content.
This invention is primarily directed to the analysis of ground meat, the composition of which may vary considerably depending on the grade. Ground fresh meat products may contain between 10 and 30 percent fat. Control of the fat content is critical to meeting both regulatory and profit objectives. In cured sausage products such as weiners and bologna, control of both fat and added moisture content is required in order to meet regulatory limits. This invention helps the user to maintain control of the aforementioned chemical components of meat products by providing accurate, timely analysis results during the formulation process.
Apart from close cost control by the processor, there is also protection of the consumer in that the amount of fat or moisture may vary in a meat product from day to day, notwithstanding the processor's good faith attempts to control these variables. In many cases of contract sales, fat content is specified and penalties imposed for exceeding the maximum amounts stated. Fat and moisture content have also been important constituents in diet control for hospitals, nursing homes, and the like. Finally, it would be advantageous, both to the processor and consumer, to have each packaged meat product labeled with the percentage of fat, moisture, and protein.
Currently, the standard determination of fat is by the "Official Methods of Analysis of the Association of Official Analytical Chemists" (AOAC) ether extraction method which takes about 8 to 24 hours for final results. The fact is that not all fats are ether extractable, while conversely, some non-fat materials are ether extractable. Accordingly, an absolute standard does not exist.
Another method which is rapid and effective is disclosed in U.S. Pat. No. 3,183,710 assigned to the assignee of this application. This latter method involves direct heating of a comminuted meat sample to melt the fat and to remove the moisture and fat in liquid form.
The method of analysis taught in U.S. Pat. No. 3,673,852, assigned to the assignee of this application, is an improvement of that method. In that patent, comminuted meat is exposed to microwave energy which vaporizes moisture in the sample and renders fat present in the sample. Use of microwave energy for this purpose enables even heating of the sample throughout without producing uneven cooking or charring of the sample. The methods and apparatus disclosed in U.S. Pat. Nos. 3,890,825 and 3,916,670, also assigned to the assignee of the present invention, represent improvements over the earlier patents. In these patents, a sample of comminuted meat is continuously monitored during cooking until the rate of weight loss of the sample decreases to a predetermined value. In this manner, reproducibility and accuracy in sample analysis is increased.
However, problems have been encountered during the monitoring of the sample. Fat rendered from the sample during cooking and collected in a beaker beneath the sample on a weighing scale repeatedly spatters and explodes. These explosions which are caused by droplets of moisture falling into the hot fat and violently boiling, induce vibrations in the weighing scale, driving weight readings through erratic fluctuations. Consequently, it becomes difficult to monitor accurately the rate of weight loss to ascertain when a predetermined value has been reached.
Additionally, the weight loss recorded during cooking represents only that loss due to moisture vaporization. For some meat samples, the moisture weight loss is relatively small so that the rate of weight loss is difficult to measure, making it more difficult to ascertain when a predetermined rate has been reached.
Accordingly, the need still exists in the art for a process and apparatus which will provide an easy and accurate analysis of the fat, moisture, and/or protein content of meat samples over a broad range of content variations.